A philosophical term of art may come in useful here. When people perceive, think, believe, and so on, these mental states are called “intentional states”, and whatever it is the particular state is about ― the percept, thought, belief ― is called the “intentional object”. So, with the wooden triangle, when we look at it from the special position, the triangle as we perceive it, that is to say the impossible triangle, is the “intentional object”. Meanwhile, the wooden thing we are actually looking at can be called the “real-world object”. So, now, with phenomenal consciousness, let us see if we cannot make a similar distinction. Suppose that, when we are conscious of having a sensation, when we say it is like something, this thing it is like is the “intentional object of consciousness.” Then, if this is in any way similar to the case of the triangle, there will be a corre-sponding real-world object ― presumably something going on in the brain ― which is what we are actually engaging with and commenting on (whether we realise this or not; of course we mostly do not).
In which case, there will indeed be a series of questions to ask further. 1. What exactly is the real-world brain activity that we are engaging with when we say it is like something? 2. Why does this activity have the ― tricky ― properties it has, such that our experience of it is as if of something so strangely private, not-of-this world and indescribable in common terms? 3. What makes this trick work? How is it done? 4. What is the point? Why was it designed like this? What can have been the evolutionary advantage of our having these marvellous experiences?
知覚と脳の働きに関係があることは間違ひないので、それを科学的に探求することは有用だ。しかし、知覚の全てが脳の働きに還元される訳ではない。脳だけで知覚が得られるのであれば、赤いトマトを見るために赤いトマトは要らない。夢で赤いトマトを見ることはあるだらう。しかし、私達は夢と現実とを区別して生きてゐる。
単なる脳の働きが主観的な、一般的な言葉で表現できない性質としてのクオリアを持つのは何故か、といふのは科学者にとつては自然な質問だ。この質問を意味のある形で議論するためには、そもそも、主観的な現象とはどのやうなものかについて、きちんとした整理が必要だと思はれる。単に「言葉にならない」と言ふだけではなく、"real-world object"とどのやうな点が異なつてゐるのかを示すべきだらう。
I believe we can already propose plausible answers to each of these questions ― although they are all quite radical. Here they are. The real-world brain activity is the activity that I have called, in my earlier writing, “sentition”.3),4) In response to sensory stimulation, we react with an evo-lutionarily ancient form of internalised bodily expression (something like an inner grimace or smile). We then experience this as sensation when we picture to ourselves ― by monitoring the command signals ― just what we are doing. Sentition has been subtly shaped in the course of evolution so as to make our picture of it have those added dimensions of phenomenality. Sentition has, in short, become what I call a “phenomenous object” ― defined as “something that when monitored by introspection seems to have phenomenal properties”. I do not pretend to know yet how this is done, or what the neural correlate of phenomenous sentition is. For what it is worth, my hunch is that re-entrant circuits in the brain are creating complex attractor states that require more than the usual four dimensions to describe them ― and that it is this that makes these “states of mind” seem to have immaterial qualities.∗)
∗) If the time course of the activity in the re-entrant circuits is described by a delay differential equation, it will typically have a hyper-dimensional attractor.
